What will it take to get phosphorous pollution out of Lake Whatcom?

Constructing systems that capture and filter runoff flowing into Lake Whatcom isn’t going to be enough to vastly reduce the amount of phosphorous in the lake that serves as the source of drinking water for nearly half of Whatcom County.

It’s also going to require other actions such as getting homeowners around the lake to voluntarily switch out their lawns for native plantings, install rain gardens or put in permeable pavement – all designed to reduce the impact of residential development by filtering phosphorous, a long-stand problem because it depletes oxygen and causes seasonal algae blooms in the lake.

The lake is the source of drinking water for about 100,000 residents in Whatcom County, including Bellingham.

The City of Bellingham, Whatcom County government and Lake Whatcom Water and Sewer District are at the end of the first year of a 50-year plan to restore the health of Lake Whatcom, which has experienced declining water quality.

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After hearing how much phosphorous has been kept out of the lake so far – for work going back to 2004 – County Council member Barbara Brenner said it seemed “overwhelming” in terms of what has been accomplished compared to what needed to be done still.

“We have a very good start,” said Cathy Craver, senior planner for Whatcom County Public Works.

Cleanup history

In 1998, the state listed Lake Whatcom as exceeding pollution standards for phosphorus, which has depleted oxygen in the lake enough to threaten fish and aquatic plants, and cause algae blooms that can gum up water-system intakes, affect the taste of drinking water and require more treatment to make the water safe to drink.

The three jurisdictions have been working over the years to improve the lake’s water quality, but the plan approved last year set the clock ticking and put an estimated price tag of $100 million on the effort for the coming decades.

The requirement, and accompanying plan, weren’t a surprise. The city, county and water district have been expecting to be directed by the state Department of Ecology, under the jurisdiction of the federal Clean Water Act, to reduce the phosphorus level coming from around the lake.

The plan required 87 percent of the developed area around the lake, about 3,500 acres, to store and filter water like a forest so phosphorous can seep into the ground instead of flowing into the lake. That’s another way of measuring the level of cleanup required, instead of using pounds.

The EPA approval gave Ecology the authority to limit the amount of phosphorous entering Lake Whatcom.

Phosphorus is a naturally occurring element found in the soil as well as human and animal waste, some fertilizer and detergents. Every time it rains some of it washes into the lake.

A forested landscape acts like a sponge and helps filter the phosphorus out of storm runoff. By contrast, stormwater glides right over roofs, driveways and lawns on its way to the lake.

Preventing stormwater runoff, then, is the main focus of the 50-year cleanup plan.

What’s being done

It will take years to restore Lake Whatcom to what it was, just as it took years for the problem to develop.

“The lake is still showing signs of residential runoff. It’s going to take time. It’s going to take more time than people want to give it. It’s the kind of patience that is very difficult,” said Robin Matthews, the lead scientist on the team that has been conducting an annual study of the lake’s water since the late 1980s, as commissioned by the city.

“You have to believe this is going to work even if you can’t see it in the next five to 10 years. It’s not what people want to hear,” Matthews, who also is the director of the Institute for Watershed Studies at Huxley College of the Environment at Western Washington University, said in an interview.

To prevent stormwater runoff, efforts include buying land to keep it from being developed, planting trees, and building the Cedar Hills-Euclid stormwater project to use bio-infiltration swales and treatment vaults to keep phosphorous out of the lake.

The revamped program will focus on homeowners in basin one and basin two of the lake, which is where most of the development are, by offering aid for more sophisticated projects such as rain gardens and filter strips. It also will be designed to be more user-friendly.

“I want to say 2.0 looks pretty fantastic,” City Council member Pinky Vargas said during the progress report. “I think we’re going to see a difference this year.”

It’s meant to encourage homeowners who aren’t building or renovating a new home – projects that need more stringent requirements for reducing phosphorous.

“There’s no trigger for them to have to do anything,” said Gary Stoyka, natural resources manager for Whatcom County Public Works. “We’re trying to get them to voluntarily do it.”

The next steps for the 50-year plan include submitting to Ecology, by the end of October, 10 years’ worth of milestones that will define adequate progress.

Additional information about challenges to Lake Whatcom, the drinking water source for about half of Whatcom County, and efforts to improve its health are online at lakewhatcom.whatcomcounty.org. In addition to focusing on keeping phosphorous out of the lake, efforts also include keeping aquatic invasive species, such as zebra and quagga mussels, out of the lake through boat inspections.

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